The present invention relates to a method and a device for more efficient and safer ways for loading, securing and unloading trailers on so-called xe2x80x9cRo-Roxe2x80x9d ships (Roll on-Roll off) and in connection with other freight operations by sea, air or train.
Today, freight by sea makes up a large proportion of the total global freight tonnage. Transportation by means of sea freight may i.a. be divided into bunker freight, container traffic and trailer freight. The latter may be defined as freight in which the goods are transported in a special transport trailer, without any appurtenant tractor unit accompanying the transport at sea. As a rule, loading an unloading takes place by means of special trucks, of so-called tug-master type, whereby trailers which are to be loaded are delivered to an indicated storage location at e.g. a harbour quay, while unloaded trailers are picked up by tractor units which transport the trailer to the final destination. Trailer freight is characterized in that the distances are relatively short, and in that it involves regular transportation with the purpose to continuously supply markets and production facilities with material. The so-called xe2x80x9cjust-in-timexe2x80x9d strategy is nowadays applied by many manufacturing companies, implying that the build-up of buffer stocks in the production units is avoided. This, in turn, places increasingly large demands on fast and reliable deliveries from the raw material suppliers. The trailer traffic by Ro-Ro vessels has therefore become increasingly large and today a huge number of trailers are loaded and unloaded all over the world.
As a rule, a Ro-Ro vessel is nowadays in harbour for twenty-four hours at the most. A large proportion of this time is dedicated to the loading and unloading of trailers. Out of the total loading time, a large proportion is consumed by the securing or lashing of trailers in order to avoid cargo shifting at sea, with the entailing risk of accident. Also when unloading, unlashing etc. consumes a considerable amount of time. All this time consumption, naturally, gives rise to large costs.
The currently used method for loading trailers comprises a tractor unit driver placing his trailer at an indicated location at a quay. At this location, the trailer is placed on supporting members which are integrally arranged on the trailer. The so-called xe2x80x9ckingpinxe2x80x9d of the trailer, i.e. the towing pin, is thereby situated at between 1100-1700 mm height from the ground. This kingpin on the underside of the trailer is intended for coupling to a so-called fifth wheel, which is arranged on the back part of a tractor unit or a loading truck. Such fifth wheels are nowadays frequently used for lorries and comprise a tapering slot at one edge which opens out into a hole, having a wear ring which describes an arc of approximately 180xc2x0 or more. When coupling up to a trailer, a tractor unit or a loading truck is manoeuvred into position so that the kingpin of the trailer, via the above-mentioned slot, gradually enters in the above-mentioned hole, whereafter a lock device is screwed tight or is tensioned so that the open portion of the arc, formed by the edge of the hole, is closed. This prevents the trailer from coming off the tractor unit. Furthermore, the fifth wheel is pivotally mounted on the tractor unit or the loading truck. A coupling of the type described makes it possible for the tractor unit or the loading truck to be turned in different directions in relation to the trailer, and additionally, to some extent, allows the tractor vehicle to be pivoted vertically in relation to the plane of the trailer.
When loading, the driver of the so-called tug-master, which is a special type of loading truck for this type of loading and unloading of trailers, collects the trailer at the quay and tows it onto the cargo deck. Since the length of the supporting members varies from trailer to trailer, the supporting members must often be cranked up when transporting the trailer from the quay to the cargo deck in order to avoid the supporting members of the trailer becoming stuck on the often upwardly bulging joint between the quay and the loading ramp or between the loading ramp and the cargo deck. When loading and unloading, a particular person is often required in order to perform this working step, i.e. to crank up the supporting members on trailers which are to be loaded.
When the loading truck has transported the trailer to its position on the deck, a trailer support, sometimes named a trailer trestle, is brought forward and is placed a distance behind the kingpin under the trailer. Thereafter, the trailer is lowered so that it rests on the support, which may have different designs within the scope of what is possible for the application. The trailer supports which are used today are not vertically adjustable which is a further reason why the integral supporting members of the trailer may have to be cranked up in order to achieve the right bearing of the trailer on the support. Trailer supports according to the prior art do not provide any special devices for latching to the deck, which is why it is necessary to secure the front end of the trailer with some kind of separate lashing means.
During the next stage, the trailer is therefore lashed to the deck by means of straps and/or chains. Chains are preferably used on the weather deck, while straps are used for the lashing on the lower decks. This stage is very labour intensive and is currently performed manually by 4 to 6 persons. The trailer is secured at 6 different points at the front part and at two points at the back part. In total 8 straps or chains are utilized which, when not in use, are available along the long sides of the cargo deck.
The working environment for the personnel working with loading and unloading, as described above, is characterized by noise from the loading truck, from the driver""s cab of which the visibility furthermore is limited which increases the risk of collision accidents and trapping injuries to other personnel on the cargo deck. Furthermore, the work is done under extreme time pressure since, as earlier mentioned, it is extremely important to be able to load and unload as fast as possible.
Procedures similar to the ones described above are also used in connection with the loading and unloading of trailers on other vessels than just cargo vessels, for instance car ferries. Also certain types of trains or transport planes may be loaded in a similar manner. In all cases, the problems are similar to the ones described above.
Thus, it is an object of the present invention to provide a safe, time-saving and cost-effective method for loading, securing and unloading trailers in connection with freight by sea, air or train.
This object of the invention is achieved by means of a method in accordance with claim 1 with the use of a trailer support which, when loading trailers, by means of a first coupling member arranged on the trailer support is coupled to a first coupling means of a loading truck, and that said trailer support by means of a second coupling means is coupled to a second coupling member of a trailer, and that at least one lock device, arranged in the trailer support, is locked to at least one of a plurality of predefined locking points arranged in the floor of a cargo space in order to achieve a securing of the front end of said trailer.
If necessary, separate cargo lashing means are utilized for securing the back end of the trailer, whereby said separate cargo lashing means comprise attachment means which are locked into the same type of predefined locking points in the floor of the cargo space as the ones used when securing the front end of the trailer by means of the lock device of said trailer support.
A further object of the present invention is to provide a device in the form of a trailer support which provides a simple and reliable support function for supporting the front part of a trailer when parked, and also comprises means which facilitates transportation of the trailer support by means of a loading truck, and that the support moreover comprises means for coupling to the underside of a trailer and for securing to a deck of a vessel.
This object is achieved by means of a device according to claim 6, in the form of a trailer support comprising a first coupling member for coupling to a first coupling means on a loading truck, and that said trailer support comprises a second coupling means for coupling to a second coupling member on a trailer, and that said trailer support comprises at least one lock device with a locking member for locking said trailer support to at least one of a plurality of locking points arranged in the floor of a cargo space.
The present invention makes it possible for a single loading truck with driver to handle the entire loading, cargo securing and unloading operation alone, something which implies large time and cost savings.